Slaves were brought from the west coast of Africa to the New World. US History I - Midterm Review. Vocabulary for US History I - Midterm Review. Find, create, and access US History I, The Federalist Papers, flashcards with Course Hero.
Breathing is an involuntary process that is controlled by the medulla and pons of the brain stem. The frequency of normal, involuntary breathing is controlled by three groups of neurons or brain stem centers: the medullary respiratory center, the apneustic center, and the pneumotaxic center.owever, if alveolar Po2 is 60 mm Hg, then arterial blood will have a Po2 of 60 mm Hg, in which case the hypoxemia is severe enough to stimulate peripheral chemoreceptors in the carotid and aortic bodies. In turn, the chemoreceptors instruct the medullary inspiratory center to increase the breathing rate.
1 Oxygen: Specialized nerve cells within the aorta and carotid arteries called peripheral chemoreceptors monitor the oxygen concentration of the blood and feed back on the respiratory centers. 2  If the oxygen concentration in the blood decreases, they tell the respiratory centers to increase the rate and depth of breathing. This mechanism prevents damage to the lungs that would be caused by over-inflation. 2  Signals from higher brain centers: Nerve cells in the hypothalamus and cortex also influence the activity of the respiratory centers. 3  During pain or strong emotions, the hypothalamus will tell the respiratory centers to speed up.